The conversion of isopentanes to alkanes (paraffins) containing fewer carbon atoms per molecule and alkanes containing more carbon atoms per molecule (i.e., the disproportionation of isopentanes) in the presence of hydrogen fluoride as a catalyst is known and has been described in U.S. Pat. Nos. 2,403,649, 2,403,650 and 3,679,771. This process has recently gained importance because of governmental regulations requiring the reduction of the amount of volatile C.sub.4 and C.sub.5 alkanes in gasoline. Thus, there is an incentive to convert isopentanes to higher isoalkanes, especially isoheptanes and isooctanes which are valuable high-octane motor fuels, and to isobutane which is a feedstock for the alkylation with olefins and also for the production of MTBE (via isobutylene). The present invention is directed to an improvement of the HF-catalyzed disproportionation of isopentane.